Resist　line　edge　roughness　(LER)　and　sidewall　roughness　of　micro/nano　structures　are　becoming　important　issues　of　increasing　concern　in　the　sub-100　nm　fabrication　regime　due　to　their　critical　impact　on　device　performance.　LER　and　sidewall　roughness　metrology　is　used　to　monitor　individual　nanostructure　fabrication.　Porous　anodic　alumina　(PAA)　membranes　are　typical　nanoscale　templates　and　can　be　fabricated　with　different　pore　sizes　through　second　oxide　technique　by　changing　the　acid　electrolyte　and　the　anodization　voltage.　The　LER　of　sidewall　inside　anodic　porous　alumina　template　holes　has　been　evaluated　by　analyzing　top-down　scanning　electron　microscopy　(SEM)　images　off-line.　And　RMS　roughness　(3σ)　and　height-height　correlation　function　are　used　to　characterize　the　sidewall　roughness　inside　nanoscale　holes　of　porous　alumina　template.　©　2011　IEEE.